Insecticidal compositions comprising diethyl thiophosphoric acid disulfide



United States Patent INSECTICIDAL COMPOSITIONS COMPRISING DIETHYL THIOPHOSPHORIC AClD DISUL- FIDE No Drawing. Application June 24, 1952, Serial No. 295,358

5 Claims. (Cl. 167-22) minutes. After heating externall twenty minutes at 80 0., th remove a small amount of insoluble material. 400 grams of the diethyl thiophosphoric acid thus prepared zed with a solution of 86 grams of sodium y for an additional e product was filtered to maintain the temperature below 40 C. The sodium salt was completely aqueous solution. 156 grams of sodium nitrite was then added portionwise to the aqueous solution with stirring.

A solution of 230 grams of concentrated sulfuric acid diluted with 108 grams of water was then added to the above solution, dropwise with stirring. The reaction mixture was cooled externally during the addition of This invention relates to new and useful improvements h id, maintaining h temperature belnw 40 1 The in parasiticidal preparations and more particularly to imdiethyl thiophosphoric id di lfid thu f d sepaproved insecticides. This invention also relates to rated as an insoluble oil. The oil was isolated, Washed methods of Protecting Organic material Subject t0 aliaflk once with water, once with 5% sodium. hydroxide and by low Orders of 'g More p y, this three'times with water. The product was then dried by vention is concerned with insecticidal compositions conblowing with nitrogen at 105 C. The resulting material taining as the active ingredient diethyl thiophosphoric gave the following analysis: aciltjihdisulfidle. f U S M is app ication is a continuation-in-part o Patent No. 2,611,729, issued September 23, 1952.

It has now been found that diethyl thiophosphoric acid disulfide is extremely eifective for checking the growth gg zf of insects. This compound is thus used as the novel ingredient of insecticidal compositions. The formula of T diethyl thiophosphoric acid disulfide is as indicated below: Example II.I nsecticldal test results with diethyl oeHso S S OCzHs thzophosphoric acid disulfide 'l l Diethyl thiophosphoric acid disulfide was tested for insecticidal activity. The values given in column I of the 021150 0013 following table represent the percentage mortality of the It is especially surprising to find that diethyl thiophostest i t after 96 hours foll wing a two-minute imphoric acid disulfide shows extremely good insecticidal merSlOIl In all 015% aqueous Solution suspenslon of activity in view of the fact that many closely related the test p u phosphoric acid derivatives show distinctly inferior in- T results Folllmn II are glven as P F secticidal activity as compared to the compound of this tality of the test IIISECt after 96 hours following bloodi ti 40 stream injection of the indicated dosages of the test com- Diethyl thiophosphoric acid disulfide may be prepared P in general by the manner of U. S. Patent No. 2,523,146 The figures in column III list the results obtained on issued September 19, 1950, i. e., by converting diethyl the Nelson drop test for house-fly toxicity. At full dosage thiophosphoric acid into a water-soluble salt, dissolving (D), 5 mg. of test material/gm. body weight is placed this salt and a water-soluble metal nitrite in water, and on the flys body (0.002 cc. of a 5% solution per fiy).

Insecticidal Activity M I II III a Cg'iitaet Insecticidal Activ- Bloodstream Insecticidal Ac House-Fly Toxicity lty, Kill ivity, Kill Nelson Drop Test Compound M M '5 Bl t a Peziplani'tus ageriglrana 6 t (l ger- 1116i can 03.0 1816/ Male! ff ggg jf f Female Female (Milkweed Female Male s) M Male Fem. 0.5 mg. 0.5 mg. 0.1 mg. D D/2.5 Diethylthiophosphoricacid disulfide- 100 100 100 40 100 100 100/100 100 100 Triethyl phosphate 0 30 20 100 /0 0/20 Tricresyl phosphate 40 20 O 20 100 100 0/10 0/10 adding a mineral acid to liberate the nitrous acid in solu- These figures indicate that diethyl thiophosphoric acid tion. The acid not only liberates the nitrous acid, but disulfide is a surprisingly eifective contact insecticide,

converts the salt into a free acid 0 disulfide reaction prod the aqueous medium.

The following examples are given to illustrate this invention and include both the preparation of diethyl thiophosphoric acid disulfide and test results obtained on its use as an insecticide.

Example I.Preparati0n of diethyl thiophosphoric acid disulfide A flask equipped with a stirrer, reflux condenser, and thermometer was charged with 276 grams of absolute ethanol and 333 grams of P285. The reaction was exothermieand the temperature rose to 70 C. within fifteen f phosphorus and the uct is precipitated as an oil from being far superior to the related compounds on Blatella germanica (German roach), Omelpeltus sociatus (milk weed bug), and the house fly. It will also be noted that the compound of this invention ingestion insecticide in the bloodstream planitus americana (American roach).

The compound of this invention is best distributed in the form of sprays such as in aqueous dispersions or dust ciampositions of the active ingredient with a powdered c ay.

Since the compound of. this invention is a water insoluble oil, it is preferable to use it admixed with wetting or emulsifying agents so as to be able to secure aqueous emulsions and consequent uniformity of dispersion in the resulting colloidal system. The use of these wetting agents also increases the spreading action of the spray by decreasing the surface tension of the liquid carrier. This results in the securing of better contact of the spray with the surface being treated, and consequently brings the active ingredient into intimate contact with the parasite life. The concentr tion of active ingredient in the aqueous emulsions varies with the insect pests to be treated. In general, the aqueous emulsion contains about active ingredient, and 1% wetting agent by weight. Thus, a typical emulsion concentrate formulation consists of 83% diethyl thiophosphoric acid disulfide and 17% petroleum sulfonate salt by weight on an active ingredient basis. This mixture can then be diluted with about 94 parts of water to 6 parts of concentrate.

The active compound of this invention can also desirably be made up in solid compositions. A dust composition containing about 5% active ingredient is made up by admixing the active compound with clays such as fullers earth, china clay, 'kaolin, or bentonite. Solid wettable powders for aqueous dispersion contain about 25-50% active ingredient, 50-75% clay, and about 1% wetting agent. Clay itself also acts as a spreading agent.

The term emulsifying agent is consequently used hereafter to connote generically, the various emulsifying agents, wetting agents and spreading agents including clays that are adapted to be admixed with the active compound of this invention in order to secure better wetting and spreading of the sprays of the active ingredients in the liquid vehicles in which they are insoluble through the lowering of the surface tension of the vehicles (see Frear-Chemistry of Insecticides, Fungicides, and Herbicides," second edition, page 280).

Among the water-soluble wetting agents that can be used are the sulfates of long-chain alcohols such as dodecanol up to octadecanol, sulfonated amide and ester derivatives, sulfonated aromatic and mixed alkyl-aryl sulfonate derivatives, esters of fatty acids such as the ricinoleic acid ester of sorbitol, and salts of the petroleum sulfonic acids known as mahogany acids. Alkali metal salts of the latter are preferred. The non-ionic emulsifying agents such as the ethylene oxide condensation prodgcts 0g alkylated phenols, alcohols or amines may also e use Solvents for the compound of this invention may be utilized as auxiliary agents if desired. Among the solvents for the compound of this invention are petroleum fractions such as kerosene, aromatic solvents such as toluene or xylene, and chlorinated hydrocarbons such as carbon tetrachloride or trichloroethylene. 1

The compound'of this invention may also be admixed with carriers that are themselves active, .such asother parasiticides, hormones, herbicides, fertilizers, and wetting agents. Stomach and contact insecticides such as the arsenates,-.fiuorid es, rotanone, and the various fish poisons and organic insecticides, such as di(p-)ehlorophenyltrichlorethane, benzene'hexachloride, and similar products may also be advantageously added. I

It is to be understood that the invention is not limited to the specific examples which have been otfered merely as illustrations, and that modifications may be made without departing from the spirit of the invention.

What is claimed is:

1. An insecticidal composition comprising diethyl thiophosphoric acid disulfide as the active ingredient admixed with an emulsifying agent which lowers the surface tension of water and thereby promotes aqueous emulsions of the active ingredient.

2. An insecticidal composition comprising diethyl thiophosphoric acid disulfide contained in an aqueous emulsion with an emulsifying agent.

- 1 3. An insecticidal dust composition comprising diethyl tlliiophosphoric acid disulfide admixed with a powdered c ay.

4. A composition as in claim 3 in which the clay is bentonite.

5. An insecticidal emulsion concentrate comprising diethyl thiophosphoric acid disulfide admixed with a petroleum sulfonate salt, said petroleum sulfonate salt being present in an amount of about /5 by weight of the diethyl thiophosphoric acid disulfide.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN INSECTICIDAL COMPOSITION COMPRISING DIETHYL THIOPHOSPHORIC ACID DISULFIDE AS THE ACTIVE INGREDIENT ADMIXED WITH AN EMULSIFYING AGENT WHICH LOWERS THE SURFACE TENSION OF WATER AND THEREBY PROMOTES AQUEOUS EMULSIONS OF THE ACTIVE INGREDIENT. 